In general, a multilayer PCB having a power semiconductor module package mounted therein has a structure in which a plurality of PCBs 1 having circuit patterns 1a, 1c of copper printed thereon are multi-layered on both side surfaces of a substrate 1a, such as FR-4, CEM-1, CEM-3, Al METAL-PCB, as shown in FIG. 1. The PCBs are configured to be electrically insulated from each other by a pre-preg 2 formed therebetween. An electronic circuit element such as an IC chip, a power semiconductor module package, or the like is mounted on the circuit pattern of the outermost PCB, and a heat radiation structure is additionally installed on a surface of the multilayer PCB structure to discharge heat generated from the electronic circuit element to the outside.
However, according to such a normal multilayer PCB structure, the respective PCBs are stacked in sequence, and accordingly, heat generated from a circuit pattern of a PCB positioned inside is not effectively discharged. In addition, there are disadvantages that, due to the presence of the heat radiation structure installed on the surface of the multilayer PCB, the PCB module has a complicated structure and the volume thereof increases.